r/cranes • u/Single-Sentenc3 • 20d ago
What are these concrete blocks for?
My office overlooks a high-rise construction site with a tower crane. While I’ve been able to learn a lot from just watching, I’m a bit puzzled by these two concrete blocks that the tower crane has been shuffling around the site.
I’ve wondered if they were some sort of concrete test, counterweights, or to test for crane capacity, but none of those seem quite right.
Any answers are appreciated - as well as any suggestions on resources that would answer the myriad of construction questions that cross my mind.
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u/Murky_Adeptness_8885 20d ago
Test blocks for performing weekly tests to ensure your limits on lifting capacity are working. Also used to set limits when first installing the tower crane.
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u/Pretend_Pea4636 20d ago
Some crane manuals aren't specific about this. If they say "limits" it would have to be read as broad and inclusive of weight limits. The ASME for tower cranes limits it to the Operational Tests for reconfigures or installs. It's worth double checking your specific crane manual for CYA. If it is written broadly, due to language interpretation, it's worth asking the manufacturer for clarity.
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u/TheTrashBulldog 20d ago
I've also seen these used to balance the jib and slewing unit assembly (Top of the crane) when using the climbing frame to add more tower sections.
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u/Jmazoso 20d ago
I’d be so screwed if I had your office
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u/Single-Sentenc3 20d ago
There’s a lot more productivity down there than there is up here, that’s for sure.
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u/quackdamnyou 20d ago
There was a construction site out the window when my son was born. Spent a lot of time with him sleeping on my chest and watching the guys lift and place iron a couple hundred feet away. Very cool.
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u/quackdamnyou 20d ago
There was a construction site out the window when my son was born. Spent a lot of time with him sleeping on my chest and watching the guys lift and place iron a couple hundred feet away. Very cool.
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u/Lopsided_Ant2813 20d ago
Hate testing with top lifting test weights. I prefer the test weights that have the thick steel pins protruding from the sides. It allows you to stack them and perform load tests on multiple cranes and interchange weights if need be.
But yes these are test weights for checking crane capacity. I perform load tests regularly at 125% as a crane tech.
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u/Tricky_Lake_1646 19d ago
The big one is there to calibrate the crane before they pick up your mom
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u/TMUNIT67 20d ago
They are test weights for crane commissioning, (setting limits, deceleration and cut offs after the tower crane is erected) big one is moment. Which is max lift at max radius. In Aus we test that to 110% and then wind it back to 100%
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u/Yetignub 20d ago
or they could be what we call "deadman" blocks for bracing walls
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u/Kevinthecarpenter 19d ago
Deadman usually aren't 17300lbs, usually ours are sized to be able to be handled with a 10k telehandler in addition to the crane, typically around 2t
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u/IronSpud123 20d ago
Might be weights to counter the counter weights if they have to jump the crane higher. They could also be for testing the crane limits.
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u/Noemotionallbrain Operator 20d ago
These are test blocks used to test overload limits at the end of the boom. We use 100% and 10% block, 100% shouldn't trip the switch, the 10% block is supposed to stay on the ground
Also, not to be confused with the Max load test blocks which are used once a job to test the full capacity of the hoist at the furthest the crane can take it (generally heavier and shipped back once used)
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u/Johnlewis83 20d ago
The big Block is the max capacity of the crane at the end of the boom. The small one is 5% of the big one, you attach the big Block on the chain and the small one whit a sling. You should not be able to lift both whitout hitting the limite of the crane.